Pressure sensors are used in a variety of applications. Typically pressure sensors are implemented in offerings requiring the measurement of pressure in relation to the operating conditions or environment of the device. Pressure sensors may often be used in medical devices, engines, electronic applications and portable implementations, for example.
For example, an ultra-miniature, piezo-resistive silicon pressure sensor die may have application in monitoring pressure from the tip of a catheter. Such a pressure sensor would typically be in communicative contact with a circuit having a memory/control logic in which there is an input and output. Pressure sensors incorporating micro-electro-mechanical systems (MEMS) have even greater utility and application. As used herein, the term pressure sensor is intended to include any pressure sensor.
While a pressure sensor may be customized or selected for its particular characteristics such as pressure range, environmental or operating conditions, communication interface, footprint, etc., often, despite careful selection over these characteristics, a pressure sensor's accuracy and stability are the two essential operating parameters. Providing for stability in a pressure sensor is an important aspect of accurately assessing an operating environment. For instance, a change of sensitivity could cause a large error to the pressure sensor and inaccurately cause other dependent devices apart of the overall system to respond inappropriately. Similarly, pressure sensors, or transducers, can also become unstable due to electrostatic charge, mechanical stresses, wiring connections and temperature changes.
Unfortunately, while accuracy of a pressure sensor is often related to the quality of the device, the stability may not be so as pressure sensors may become unstable during assembly, operation, or even during packaging, the instability typically resulting from a sensor sensitivity shift.
Therefore what is desired is an approach to improve the stability of a pressure sensor by compensating a pressure sensor's sensitivity shift due to packaging and/or assembly by stabilizing the sensitivity and reducing the error caused by strain-related sensitivity shift. Additionally it would be further desired to have an approach that will also provide for eliminating the sensitivity calibration of a pressure sensor after packaging or assembly, such that the option of providing for less costly packaging may be realized.